1. Field of the Invention
The present invention relates to hand-guided sweeping machines, and, particularly, to sweeping machines of the type employing a rotary-driven cylindrical brush to propel debris into a detachable hopper, a blower (fan) for drawing a suction airstream through the machine to facilitate pickup of dust, and a filter disposed to remove dust from the airstream prior to passing through the blower.
2. Description of the Prior Art
In general, hand-guided sweeping machines including a hopper disposed to receive debris propelled by a rotary-driven cylindrical brush, a fan for drawing a suction airstream through the hopper and a filter disposed above the hopper, are known. In such sweepers, particles collected by the filter fall or may be shaken down into a receptacle.
An example of such a prior art sweeper is described in U.S. Pat. No. 3,189,931, issued on June 22, 1965 to R. C. Peabody. In that sweeper, a filter housing is integrally attached to the hopper. When the hopper is to be emptied, the receptacle and filter housing are manipulated as a unit and moved out of proximity with the inlet to the blower.
Another example of a prior art sweeper is described in U.S. Pat. No. 4,580,313, issued on April 8, 1986 to M. L. Blehert. Such prior art sweepers employ a box-shaped filter housing disposed immediately above the hopper. The lower wall of the housing is sloped downwardly and forwardly to communicate at its forward end with the hopper. The filter housing is hingedly secured at its rear upper end to the frame of the sweeper in proximity to the blower inlet, and is freely, but sealingly, engaged at its front lower end with the hopper. The filter housing may be pivoted upward into a raised position to permit the hopper to be tipped for emptying or removed from the sweeper. The filter housing cooperates with a vibrator to shake collected dust particles from the filter and convey the dust along a sloped lower wall of the housing into the hopper.
Such prior art sweepers, however, are disadvantageous in that they tend to be unwieldly, or relatively expensive, and tend to be susceptible to dust entering the blower mechanism when the filter housing is removed or raised to empty the hopper. Further, in the case of the prior art sweepers employing a hinged filter housing, the housing inlet is removed from registry with the hopper opening. Accordingly, dust from the filter shaken loose when the housing is tilted is not collected in the hopper, but rather tends to disburse over the surrounding area, and internal components of the sweeping machine.